The present invention relates to computer networks, and more particularly to a method and system in an Internet Protocol (IP) network for automatically configuring a Telecommunications Network (xe2x80x9cTelnetxe2x80x9d) 3270 client to access a desired Systems Network Architecture (SNA) application among a plurality of possible SNA applications through an appropriate Telnet 3270 client.
SNA and IP Environment
Every day, for all sorts of reasons, more and more companies are focusing on the consolidation of the multiple specialized networks they directly operate or lease from service providers onto a single protocol network. These multiple specialized networks are based on diverse networking technologies such as Systems Network Architecture (SNA), Internet Protocol (IP) or Internetwork Packet Exchange (IPX).
These companies are making this consolidation one of their top priorities. Companies are almost exclusively selecting the Internet Protocol (IP) as their protocol of choice. However, for the overwhelming majority of these companies using SNA protocols and applications, there still is and will be for the many years to come, a major requirement in this changing environment. The requirement is for the employees of these companies to keep the capability they always had to access the huge amount of existing corporate data residing in traditional mainframes and accessible through SNA applications.
TCP/IP
The Internet is a global network of computers and computers networks. The Internet connects computers that use a variety of different operating systems and languages, including UNIX, DOS, Windows, Macintosh, and others. To permit communication among these various systems and languages, the Internet uses a standard language referred to as TCP/IP (xe2x80x9cTransmission Control Protocol/Internet Protocolxe2x80x9d). The TCP/IP protocol supports three basic applications on the Internet: transmitting and receiving electronic mail, logging into remote computers (xe2x80x9cTelecommunications Networkxe2x80x9d or xe2x80x9cTelnetxe2x80x9d), and transferring files and programs from one computer to another (xe2x80x9cFTPxe2x80x9d or xe2x80x9cFile Transfer Protocolxe2x80x9d).
World Wide Web
With the increasing size and complexity of the Internet, tools, often called navigators or navigation systems, have been developed to help find information on the network. Navigation systems that have been developed include programs such as Archie, Gopher and WAIS. The World Wide Web (xe2x80x9cWWWxe2x80x9d or xe2x80x9cthe Webxe2x80x9d) is a recent superior navigation system. The Web is:
an Internet-based navigation system,
an information distribution and management system, and
a dynamic format for communication.
The Web seamlessly integrates several forms of information, including still images, text, audio and video. A user on the Web using a Graphical User Interface(xe2x80x9cGUIxe2x80x9d, pronounced xe2x80x9cgooeyxe2x80x9d) may transparently communicate with different host computers on the Internet different system applications (including FTP and Telnet), and different information formats for files and documents including, for example, text, sound and graphics.
Hypermedia
The Web uses hypertext and hypermedia. Hypertext is a subset of hypermedia and refers to computer-based xe2x80x9clinksxe2x80x9d through which uses move from one place to another in a document, or to another document, in a non-linear manner. To accomplish this feature, the Web uses a client-server architecture. The user""s computer is said to be a client computer to the Web server computer. Web servers enable a user to access hypertext and hypermedia. The clients send requests to the Web servers, which in turn react, search and respond. The Web allows client-based application softwares to request and receive hypermedia documents (including formatted text, audio, video and graphics) from a Web file server with hypertext link capabilities to other hypermedia documents.
The Web, then, can be viewed as a collection of document files residing on Web host computers that are interconnected by hyperlinks using networking protocols, forming a virtualxe2x80x9cwebxe2x80x9d that spans the Internet.
Uniform Resource Locators
A resource on the Internet may be unambiguously identified by a Uniform Resource Locator (URL), which is a pointer to a particular resource at a particular location. A URL specifies the protocol used to access a server (e.g. http://, ftp://, etc.), the name of the server (e.g. www.ibm.com, and the location of a file on that server (e.g. /products/catalog.html).
Hyper Text Transfer Protocol (HTTP)
Each Web page may appear as a complex document that integrates many media, for example, text, images, sounds and animation. Each such page may also contain hyperlinks to other Web documents, so that a user at a client computer may click on icons using a mouse and may activate hyperlink jumps to a new page (which is a graphical representation of another document file) on the same or a different Web server.
A Web Server is a software program run on a Web host computer that responds to requests from Web Clients, typically over the Internet. All Web servers use a language or protocol to communicate with Web Clients which is called HyperText Transfer Protocol (xe2x80x9cHTTPxe2x80x9d) graphics, sound and video. All types of data, including HyperText Markup Language (xe2x80x9cHTMLxe2x80x9d), can be exchanged among Web servers and clients using this protocol. HTML describes the layout, contents and hyperlinks of the documents and pages to be displayed to the user. When browsing, Web Clients convert user-specified commands into HTTP GET requests, connect to the appropriate Web Server to obtain the information, and await a response. The response from the server may be the requested document or an error message. After a document or an error message is returned, the connection between the Web client and the Web server is closed.
The first version of HTTP is a stateless protocol. That is to say, with HTTP version 1.0, there are no continuous connections between clients and servers. A Web client using HTTP receives a response as HTML data or other data. Newer versions of HTTP break this barrier of a stateless protocol by keeping the connection between the server and client alive under certain conditions.
Browser
After receipt, the Web Client formats and presents the data or activates an ancillary application, such as a sound player, to present the data. To do this, the server or the client first determines the type of data to be received. The Web Client is also referred to as the xe2x80x9cWeb Browser,xe2x80x9d since it in fact browses documents retrieved from the Web Servers.
Telnet 3270
A widely used technique for the transport of SNA information across an IP network is the use of Telnet technologies, specifically the Telnet3270 (xe2x80x9cTN3270xe2x80x9d) emulation. This technique for SNA xe2x80x9cgreen screenxe2x80x9d workstation users utilizes a Client/Server approach. xe2x80x9cHost-On Demandxe2x80x9d from IBM or xe2x80x9cWeb clientxe2x80x9d from CISCO are examples of Client software implementations. Network Utility from IBM or CISCO router""s offerings are typical server implementations (hardware and software). The xe2x80x9cTN3270 Clientxe2x80x9d software usually runs within the customer""s workstation while thexe2x80x9cTN3270 Serverxe2x80x9d software is usually placed in front of the customer""s data center mainframes (or sometimes directly within the mainframe itself) or within the customer""s branch offices.
As illustrated in FIG. 1, IP protocols are used between the TN3270 Server 102 and the TN3270 Clients 101, while traditional SNA protocols are used between the TN3270 Server 102 and the target SNA applications 103. More information concerning Telnet, TN3270 and Network Utility can be found in the following publications, incorporated herewith by reference:
xe2x80x9cTCP/IP Tutorial and Technical Overview,xe2x80x9d Martin W. Murhammer, Orcun Atakan, Stefan Bretz, Larry R. Pugh, Kazunari Suzuki, David H. Wood, IBM International Technical Support Organization, October 1998, GG24-3376-05.
xe2x80x9cIBM 2216/Network Utility Host Channel Connection,xe2x80x9d Erol Lengerli, Jacinta Carbonell, Thomas Grueter; IBM International Technical Support Organization, January 1999, SG24-5303-00.
xe2x80x9cIBM Network Utility Description and Configuration Scenarios,xe2x80x9d Tim Kearby, Peter Gayek, Gallus Schlegel, Imre Szabo, Zhi-Yong Zhang; IBM International Technical Support Organization, January 1999, SG24-5289-00.
xe2x80x9cInternetworking with TCP/IP-Volume I-Principles, Protocols, and Architecture,xe2x80x9d Douglas E. Comer, Second Edition, Prentice Hall 1991.
Requests For Comments (RFCs) from the Internet Engineering Task Force (IETF):
RFC 1576: TN3270 Current Practices,
RFC 1646: TN3270 Extensions for LU name and Printer Selection,
RFC 1647: TN3270 Enhancements, and
RFC 2355: TN3270 Enhancements.
Accessing SNA Applications via Traditional SNA End-to-End
In the traditional SNA world, user workstations traditionally obtain access to SNA applications by connecting first to an intermediate application. This intermediate application provides for access to the real target application. This intermediate application, also referred to as an Intermediate Selection Application, usually displays to the user a selection screen which lists the SNA applications that may be accessed. The user selects from that menu the target SNA application he wants to access and is then connected to that target SNA application, which usually presents to the user an application welcome screen (for instance displaying the SNA application name and asking for a user logon and password). FIG. 2 describes a traditional SNA access to an Intermediate Selection Application in an SNA environment.
First step 201: The user is presented a Selection Screen of a plurality of possible applications by the Intermediate Selection Application (three possible applications A, B and C). Usually, the workstation automatically sets up a direct connection to the Intermediate Selection Application, as soon as the workstation""s SNA protocol stack is started (or, in case of a xe2x80x9cdumbxe2x80x9d terminal, when the terminal is powered on). Second step 202: Provided that at this time the Intermediate Selection Application is up and running, the connected user selects an application (application A) by typing an application name on the selection screen. Third step 203: Finally, the user is connected to the desired application (application A), which usually presents to the user an application welcome screen.
Accessing SNA Application from TN3270 Client with Manual Configuration
TN3270 clients can be manually configured with the IP address or name of the TN3270 Server to be accessed in order to reach the target SNA application. The main drawback is that the TN3270 Server selection is static and has to be manually changed for each SNA Application the user wants to access. This situation seriously complicates the administration of networks comprising a plurality of user workstations. Furthermore, since the configuration is manual on each TN3270 Client, there is no way to easily control the TN3270 Servers"" load (manual configuration may, for instance, result in some under-used TN3270 Servers, while at the same time other TN3270 Servers may be overused).
Accessing SNA Application from TN3270 Client with Dynamic Configuration
In a TN3270 Client-Server approach, one technique commonly applied is to provide the Intermediate Selection Application via a Web Server implementation. In such a case, the user accesses the Intermediate Selection Application within the Web Server, using his favorite Web Browser running on his user workstation. This approach is described in FIG. 3: First step 301: The user receives a Selection Screen on the Web Browser from the Intermediate Selection Application in the Web Server. The selection screen may offer three applications: A, B and C. By selecting the desired SNA Application from the Selection Screen (just a click from within the Browser), the workstation obtains the IP addressing/naming information corresponding to the preferred TN3270 Server for the desired target SNA application. Second step 302: If the user chooses application C from the Selection Screen, the user workstation obtains from the Web Server the address (SS) for the TN3270 Server(s) (providing access to the mainframe-housed application C). Third step 303: Thus, the local TN3270 Client can be started either manually or automatically to access the preferred Telnet server by using the address provided by the Intermediate Selection Application. The user workstation receives back the address of the Telnet server (Server S whose address is SS) and connects to the target application C via the appropriate server (Telnet Server S). The target application C then presents an Application Welcome Screen to the user (for instance, displaying the SNA application name X and asking for a user login and password).
Going through an Intermediate Selection Application shields end-users from changes that inevitably occur, for example when an SNA application is changed from being run on one server to another server in a different location or when a new SNA application is added. In such cases, only the Selection Screen is modified and changes in target application locations are completely transparent to the users. The workstations"" configurations are not impacted by changes in target application locations.
The draw back of this solution is that the end user must first manually connect to a Web Server in order to get the Selection Screen before launching the TN3270 Client. This xe2x80x9cmenu drivenxe2x80x9d approach forces the user to go through the Selection Screen before accessing the target SNA Application. Moreover, some form of workstation customization is usually required in order to launch the TN3270 Client from the Web Browser (for instance, setup of Java applets or association of the Web Browser application with the TN3270 Client).
CROP Problem
The problem is to provide a system and method for automatically configuring a TN3270 Client to access a desired SNA Application. Current solutions address this problem only partially. TN3270 Clients can be manually configured with the target TN3270 Server. The main drawbacks of this solution are as follows:
(a) there is no dynamic TN3270 Server selection;
(b) when the TN3270 Server fails, a manual reconfiguration of the TN3270 Client is required; and
(c)TN3270 Server names must be known and manually configured by end users, for each SNA Application the user wants to access.
TN3270 Clients can also be dynamically configured to use the TN3270 Server corresponding to the desired SNA Application, using an Intermediate Selection Application running on a dedicated Web Server. The main drawbacks of this solution are as follows:
(a) The connection with the SNA Application is indirect, since the end user must first manually connect to a Web Server to receive the Selection Screen;
(b) Connection to the Web Server must be done each time the end user wants to access an SNA Application;
(c) Some form of workstation customization is usually required in order to launch the TN3270 Client from the Web Browser (for instance setup of Java applets or association of the Web Browser application with the TN3270 Client);
(d) The Web Server running the Intermediate Selection Application may be unreachable, unavailable or too busy to process the application selection. As there is no local copy of the Intermediate Selection Application in the Web Browser, any problem on the Intermediate Selection Application may result in a service interruption (unless the Intermediate Selection Application is locally saved within the user""s workstation);
(e) The network maybe slow, leading to unacceptable response time for the user to access the Web-based Intermediate Selection Application in order to select the target application at the time the user needs to connect (unless the Intermediate Selection Application is locally saved within the user""s workstation);
(f) The user may be connected by modem to the network and due to bandwidth constraints, may prefer not to add the download time associated with an Intermediate Selection Application phase (unless the Intermediate Selection Application is locally saved within the user""s workstation); and
(g) Some companies do not wish to install Web Browsers on every user workstation due to the administrative burdens. Further, some companies do not wish to give all of their employees access to the public Internet or to the company intranet.
The present invention relates to dynamic TN3270 Client configuration and, more particularly, to a system and a method for automatically configuring a TN3270 Client to access each desired SNA application through an appropriate TN3270 Server. The present invention also relates to a configuration feature (also called an Automatic Server Configuration option) in a TN3270 Client designed to automatically retrieve a configuration code (called an Autoserver code)in order to configure the TN3270 Client to access desired SNA applications through appropriate TN3270 Servers. The present invention uses a CGI (Common Gateway Interface) program on an Autoserver URL (Universal Resource Locator) system for dynamically creating an Autoserver code (preferably in Javascript language). The Autoserver code is used by the TN3270 Client to associate an appropriate TN3270 Server with each desired SNA application.
The present invention addresses the drawbacks of the existing solutions by providing a system and a method for automatically configuring a TN3270 Client to access desired SNA applications. The automatic configuration of the TN3270 Client allows the user to directly access an SNA application without having first to connect to an Intermediate Selection Application and Selection Screen. The present invention also provides the following advantages:
(a) The user connects to the SNA application in a single operation. The Selection Screen is eliminated and, therefore, the end user does not go through a manual connection to an Intermediate Selection Application.
(b) The TN3270 Client is configured manually only once with the address of the Autoserver URL system. With the Automatic Server Configuration option, there is no need to reconfigure the TN3270 Client each time the user wants to access a different SNA application, or each time there is a change in the location of either the SNA application or the TN3270 Server.
(c) The TN3270 Server names do not have to be known or manually configured by end users. A backup TN3270 Server can automatically be defined in the TN3270 Client configuration.
(d) Centralized control may be exercised by a System Administrator of the designated TN3270 Servers, since the TN3270 Server selection is automated. This fact enables a control of the TN3270 Servers loads, since alternate TN3270 Servers can be designated by the System Administrator when additional users require access to the same SNA Application.
(e) The Autoserver code can be periodically and dynamically updated in the Autoserver URL system and in the TN3270 Client.
(f) Since there is no need for an Intermediate Selection Application system, the access to an SNA application is not slowed down by such an Intermediate Selection Application system being unavailable or overloaded.
The TN3270 Client need connect only once (when it is launched) to the Autoserver URL (Uniform Resource Locator) system in order to receive the Autoserver code. The TN3270 Client can use a local copy of the Autoserver code if the Autoserver URL system cannot be reached. This saved information can be preserved even when the user""s workstation is powered off and on again.
The manual configuration of the TN3270 Client with the Automatic Server Configuration option is simplified. The only required information is the URL (Universal Resource Locator) of the Autoserver system. A Web Browser is not required on the user workstation. Only the TN3270 Client is required. There is no workstation customization required for launching the TN3270 Client from a Web Browser, since the Web Browser is no longer required.
The foregoing has outlined rather broadly the features and technical advantages of the present invention in order that the detailed description of the invention that follows may be better understood. Additional features and advantages of the invention will be described hereinafter which form the subject of the claims of the invention.